The present invention broadly relates to continuous casting, and more specifically, pertains to a new and improved method and apparatus for the continuous casting of metal between two axially parallel cooled drums or cylindrical rolls.
Generally speaking, the method of the present invention relates to the continuous casting of metals, especially of steel strands in the form of a band or thin slabs, between two axially parallel cooled drums or cylindrical rolls whose mutually confronting outer surfaces are moved in the direction of feed of molten metal at substantially the withdrawal or extraction speed of the strand being cast. The liquid metal is introduced into a hollow mold chamber delimited by the two drums or cylindrical rolls and the cast band or slab is held against the outer surface of one of the drums or cylindrical rolls after passing the narrowest spacing or gap of the drums or cylindrical rolls.
In other words, the method of the present invention comprises the steps of feeding molten metal into a hollow mold chamber delimited by two axially parallel cooled rolls, moving mutally confronting outer surfaces of the two axially parallel cooled rolls essentially uniformly in the direction of metal feed at substantially the speed of withdrawal or extraction of the strand being cast and restraining the cast strand against the outer surface of one roll of the two axially parallel cooled rolls subsequent to passage through a location of closest roll spacing.
The apparatus of the present invention is capable of performing the method of the invention as described above. This inventive apparatus for the continuous casting of metal, especially of steel strands in the form of a band or thin slab, comprises two axially parallel cooled rolls arranged to form a gap or space therebetween, said gap having a pouring inlet side and a strand outlet side, and a molten metal feed device or apparatus. The two axially parallel cooled rolls form, conjointly with the feed apparatus, a hollow mold chamber or compartment on the pouring inlet side of the gap. The two axially parallel cooled rolls form, along an outer surface of one of the two axially parallel cooled rolls, an arcuate strand guide on the strand outlet side of the gap.
A method and apparatus for the continuous casting of metals, especially of steel bands, is known from the German patent publication No. 2,063,591, published July 15, 1971. Steel is cast or poured into a hollow mold chamber between two cooled, axially parallel drums. The mutually confronting outer surfaces of these drums move uniformly in the direction of metal feed at the withdrawal or extraction speed of the strand being cast. The cast and at least predominantly solidified band is held against the outer surface of one of the drums after passing the location of closest drum spacing. If this method is to yield a sufficient casting capacity for mass production, it can only be used for casting thin bands. For thicker bands or thin slabs of, for instance, 10 mm. or more in thickness, this method is not suitable for the casting capacity necessary for the rational mass production of steel, since it is based on the extensive to complete solidification of the cast strand at the exit from the gap. If the casting speed is increased, then the solidified strand crust or shell becomes increasingly thinner at the exit from the gap. Bulges, caused by the pressure of the still liquid core, and the ensuing metal breakouts then can not be avoided. An increased casting speed increases the frequency of malfunction in the method described to such an extent that economical production is not possible.